This invention relates to improvements in solder alloys containing copper as a major constituent.
Solders are generally classified according to the melting temperature into two groups: hard solders including iron and copper-base solders and soft solders such as low-melting-point solders containing tin as a major constituent.
Low-melting-point solders are desirable for ease of soldering operation but are poor in mechanical strengths while hard solders, such as iron and copper solders have both a melting point exceeding 1000.degree. C. though they exhibit good mechanical strengths. Yet other solders containing silver as a major constituent, are expensive though they melt at lower temperatures compared with iron and copper solders.
Moreover, hard solders previously available have not always been satisfactory despite the mechanical properties they exhibit, particularly in cases where soldered parts are subsequently subjected to heat treatment as often is the case with steel members soldered together.